Build a full game (code, art, audio) with AI

Task prompt given to the agent (headless, offline, synthetic fixture inputs): Game jam, scaled down: in one pass build a complete small arcade game as a single file index.html (no external assets or libraries). Theme: "a capybara crossing a river". Must include: a title screen with Start, keyboard controls, procedurally drawn art on a <canvas> (no image files), at least 2 sound effects and background music generated with the Web Audio API (start audio on user gesture), a score, increasing difficulty, a game-over screen with restart, and a high score saved in localStorage. Inspired by https://x.com/qusaxz/status/2077427986689843623 (unverified; not checked with the author). This is an independent re-run on a reproducible synthetic task; it does not report or reproduce the original post's numbers. Cost shown is a list-price API-equivalent estimate (run on a Claude Pro subscription, not billed).

Success criteria: All automated rubric checks pass: single file, no external libs/assets; canvas drawing; Web Audio; oscillator music/sfx; title/start screen; game over + restart; localStorage high score; capybara theme; no uncaught console errors.

Best model for this task so far: Gemma 4 31B Instruct (Venice) (success, $0.0049, 3m). Best AI model for Games & Simulations →

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All runs (8)

88% pass rate across 8 eligible runs: 7 pass, 0 partial, 1 fail. Partial and failed runs are listed below with everything else.ⓘ